The enzyme asparaginase is widely used in cancer chemotherapy. The mechanism of action of this enzyme is being studied in order to better understand the parameters which control its activity. Detailed kinetic studies, including pH and substrate concentration dependence, are being conducted. Chemical modification with reagents such as acetic anhydride, fluorodinitrobenzene, difluorodinitrobenzene, and others is being used to probe for functional groups at the active site of the enzyme.